Peter McGuffin, who died at the age of 74, showed how important it is to try to determine how genetic and non-genetic factors work together to predispose people to psychiatric disorders: so-called gene-environment interplay. He was also one of the first to see the potential of the DNA revolution to understand psychiatric disorders, and his work laid the foundation for the application of genomics to psychiatry.
Earlier it was assumed that depression could be divided into two forms: one the result of unfavorable circumstances (reactive depression) and the other the result of intrinsic factors such as genetic risk (endogenous depression).
Work at the Institute of Psychiatry in London during the 1980s, Peter showed that this is not the case, and that adverse circumstances and genetic risk often work together to increase the likelihood of depression.
These findings implied that biological treatments, such as antidepressants, as well as approaches to prevention and treatment based on reducing exposure to, or the impact of, adverse circumstances, are likely to be broadly applicable to depression.
He also found that adversity as well as depression tends to run in families. In later work in Cardiff, he and his wife, Anne Farmer, an academic psychiatrist with whom he published many papers, showed that the explanation for this is complex, and adverse events reflect a combination of a risk-prone lifestyle,’ a tendency to – experience adversity and a tendency for adverse events to be shared by family members. This pointed to the need for a much more careful dissection of gene-environment interactions.
Psychiatric diagnoses are largely made on the basis of clinical symptoms and signs rather than special investigations such as brain scans or blood tests. Nevertheless, it was widely believed that the different diagnoses identified different conditions.
Peter’s work with twins in the 90s challenged this conclusion when he showed that the genetic components of schizophrenia and bipolar disorder overlap, as well as that there are components specific to each syndrome.
He then observed a similar pattern of shared and specific genetic components in bipolar disorder and major depression. These findings were among the first to point to the now widely accepted view that our current diagnostic approaches do not clearly define disorders and that we need better ways of defining serious mental illness.
Until the 90s, research into the causes of child psychiatric conditions focused largely on social and psychological factors. Peter undertook influential research, again using twin studies, which demonstrated the additional need to consider biological and especially genetic factors.
He showed that genes influence the occurrence of depressive symptoms in children, but that the genetic effects, although particularly important in adolescence, are much less in younger children. He also conducted some of the earliest studies demonstrating the heritability of ADHD, paving the way for subsequent genomic work identifying specific genetic risk factors.
Born in Belfast, Peter was the eldest of three children of Martha (née Burnison) and William McGuffin, a merchant navy officer. When William was appointed a Trinity House pilot for the Port of Southampton in 1959, they moved to the Isle of Wight. From Sandown grammar school he went to medical school at the University of Leeds, where he met Anne. They married in 1972, the year he graduated.
In his subsequent training he became interested in genetics, and while a junior doctor with Anne carried out a genetic marker study of schizophrenia suggesting an association with the HLA system, a finding later confirmed by genomic studies.
He completed his training as a psychiatrist at the Maudsley Hospital, London, received a Medical Research Council scholarship to study genetics, and then became an MRC senior clinical fellow at the Institute of Psychiatry (now the Institute of Psychiatry , Psychology and Neuroscience and part of King’s College in London).
In 1987 he was appointed to the Chair of Psychological Medicine at the University of Wales College of Medicine in Cardiff (now part of Cardiff University), a post he held until 1998, when I succeeded him. During this period he laid the foundation for Cardiff to become a center of excellence in psychiatric genetics and trained several young researchers who go on to make important contributions to this field.
While in Cardiff he was one of the founders of the International Society of Psychiatric Genetics and its second president. He was quick to see that the application of genomics would require large-scale international collaboration and established a European Science Foundation program to bring together psychiatric genetics research across Europe in the 80s and 90s. This laid the foundation for international cooperation that continues successfully to this day.
From Cardiff he went to head the MRC Social Genetic & Developmental Psychiatry Research Center (SGDP) in London.
This was entirely appropriate, since his early work on depression was a major stimulus for the establishment of this center, whose goal is to integrate genetics with social and developmental research. He led the SGDP with great distinction and developed a supportive and nurturing environment that allowed its many stars to shine, while also developing the careers of numerous students and junior scientists.
The SBP expanded under his leadership and gained international recognition for its excellence in multidisciplinary psychiatric research, and Peter successfully raised the funding for a new building to house it.
His skills as an administrator were recognized by his appointment in 2007 as dean of the Institute of Psychiatry, a position he held for three years, during which he saved the IOP from a financial crisis. Through it all he remained a prolific researcher, stepping down as director of the SBP in 2012, and as a consultant psychiatrist in 2014. Two years later he was appointed CBE.
He is survived by Anne, their three children, Catrina, Liam and Lucy, and five grandchildren.
